HIGH-DEGREE AV BLOCK COMPLICATING CARDIAC-SURGERY OR INTERVENTIONAL CATHETERIZATION - LONG-TERM FOLLOW-UP OF UNDERLYING AV-CONDUCTION STATUS AFTER PACEMAKER IMPLANTATION

Longterm Follow-Up of Underlying AV-Conduction Status After Pacemaker Implantation. This is a retrospective report on 38 patients (pts) with different cardiac diseases who underwent pacemaker implantation becau se of high (2 degrees and 3 degrees) degree atrioventricular (AV) bloc k complicating cardiac surgery or catheterization. The study followed to objects: to describe a typical population affected with this compli cation and to investigate the chronic postoperative time course of int rinsic AV conduction after pacemaker implantation. Twenty-nine adults and 9 children were investigated. Surgical procedures in the adult gro up were aortic valve replacement (n=15), mitral valve replacement (n=6 ), mitral and aortic valve replacement (n=2) and coronary artery bypas s grafting alone in 4 pts. One patient underwent balloon aortic valvot omy, another patient with HOCM had percutaneous transcoronary septal b ranch occlusion. 38% of all adult patients had intraventricular conduc tion defects prior to the operation which caused AV block. Indications for pacing were postoperative 2 degrees AV block in 4 pts and 3 degre es AV block in 25 pts. In the children's group 5/9 pts had surgical re pair of ventricular septal defect, two pts underwent outflow tract mye ctomy, one child had correction of a partial AV canal and another one underwent arterial switch operation. All children postoperatively reve aled complete heart block. Long-term follow-up (adult group: 37 months , children: 196 months) of the intrinsic heart rhyhtm after permanent pacemaker implantation revealed presence of high degree AV block in al most all (96%) adult patients and in the majority (67%) of children, w ho had high degree AV block documented by multiple routine ECG recordi ngs following surgery or catheter intervention. In a small subgroup of 6 adult patients with a short intermittent loss of AV conduction in t he postoperative period, AV conduction recovered and no episode of hig h degree block could be found during follow-up.